Method of making printing forms



June 29, 1937.

METHOD OF MAKING PRINTING FORMS Filed Feb 27, 1931 2 Sheets-Sheet l Lmm, I, lllmlm; "In mm M mq INVENTOR ATTORNEY o. R. SCHULTZ v 2,085,048.

June 29, 1937. Q sc u -rz 2,085,048

METHOD OF MAKING PRINTING FORMS Ffile'd Feb. 27, 1951 2 Sheets-Sheet 2INVENTOR x114 ATTORNEY Patented June 29, 1937 UNTED srATEs PATENT OFFICECellu-Type Plate Inc., Union City, N. .l'.,

a corporation of New York Application February 2'7, 1931, Serial No.518,649

18 Claims.

This invention relates to printing forms and more particularly to aprinting form adapted to be applied to a printing cylinder or similardevice, and to a method of constructing the printing 5 form. V

' A molded or engraved printing form of cellulosiccomposition attachedto a printing cylinder constructed in accordance with this invention hasbeen found to produce excellent and high quality printing work for onecolor or one tone printing half tone (letter press) and intaglioprinting (rotogravuring). Where the printing form is to be used formulticolor printing it is desirable to mount the same on anon-stretchable backing so that any tendency of the printing form tostretch during use will be prevented.

Furthermore, where the printing work is heavy, as in the printing ofdesigns on fabrics, composition materials and metal, printing plates ofunusual strength are required. For such duty, whether multicolor ormonotone, the ordinary printing plates heretofore used are notsufficiently rigid and strong to insure good work.

An object of my invention is to produce a printing form which will notstretch, shrink, or otherwise become distorted under the most severeoperating conditions.

Another object of my invention is to provide a printing form especiallyadapted for multi- 9 color printing and gravuring work.

Another object of my invention is to produce a printing form especiallyadapted for muti-color printing, which, when aseries of my printingforms are secured upon the respective color cyl- 35 inders of theprinting press, exact and precise registry of the color parts on theprinted work will result.

Another object of my invention is to provide a printing form especiallyadapted for color work 40 which will not stretch, shrink, or becomedistorted under the most severe operating conditions, which is strongand durable in construction, and which can be quickly and easily made ofinexpensive materials by ordinary'labor.

Still another object of my invention is to devise v a method of makingprinting forms for multi color work quickly and'easily, with inexpensiveequipment, with few manual operations, and with the use of unskilledlabor.

Other objects of this invention will become apparent as the disclosureproceeds.

In accordance with my invention; I provide a backing plate, which has alow co-efilcient of expansion and which will not stretch under severe 5pressure strains. A thin sheet of cellulosic matemanner now used in therial having a smooth and glass-like top surface is secured to theroughened side of the backing plate. The embossing is then placed uponthe glass-like surface of the cellulosic material in the art. In makingmy printing form the backing plate is laid flat upon a table top whosesurface is absolutely level. A cellulose solution of easily flowingviscosity is poured on the roughened backing plate at approximately thecenter thereof, allowed to flow freely over the entire surface of thebacking plate and thus to assume its own level. Drip pans are providedto catch the overflow. The cellulose solution is then permitted to set,harden and freeze to the backing plate. The cellulose material whenhardened will present a top surface which is glass-like in appearance,and absolutely smooth and uniform.

The smooth cellulosic surface of the plate thus constructed is placedover the copy relief, and a viscous cellulose composition or dopematerial is disposed between the plate and the copy relief. The plate isthen rolled or pressed into contact with the copy relief, and the moldedimpression is cast in and formed by the dope material. Satisfactoryresults have also been obtained by placing the backing plate directlyover the copy relief, placing dope" material between the backing plateand the copy relief and then rolling or pressing the backing plate intocontact with the copy relief. It is understood that in such case backingplates should be selected to which the viscous plastic mass, which takesthe printing impressions, has an afflnity. For example, as above noted aviscous cellulose composition will adhere to a cellulose backing sheetand the viscous composition can be pressed between the cellulose backingsheetand the copy relief. The dope material is then allowed to set,harden and freeze to the roughened surface of the backing plate. Thelayer of dope material when hardened must be of sufficient thickness totake the full embossed impression, and in addition fully andhomogeneously cover the backing plate. It is understood that whereviscous cellulose composition is used a cellulose backing sheet is firstprovided or formed and the cellulose sheet may either be attached to amore rigid backing, such as metallic or fibrous material, before themolding operation, or after the molding operation, as desired.

In order that a clearer understanding of my invention may be had,attention is hereby directed to the accompanying drawings, forming apossible embodiments of my invention.

Referring to the drawings, Figure 1 is a top face view of my backingplate showing the top surface thereof granulated or roughened;

Figure 2 is a diagrammatic illustration of one method which may be usedin pressing the backing plate into contact with the copy relief so thatthe dope material disposed therebetween will take the embossedimpression;

Figure 3 is an enlarged diagrammatic view of my completed printing formcarrying the embossed impression;

Figure 4 illustrates one method of making a printing form of modifiedconstruction, the view, showing more particularly a casting table withthe backing plate lying fiat thereon, and with cellulosic materialin'solution flowing over the backing plate;

Figure 5 is a top face view of my modified backing plate as removed fromthe casting table, showing in particular the glassy surface of thecellulosic material after becoming frozen to the roughened backing;

Figure 6 is a side view of my modified backing plate showing moreclearly the cellulosic material superimposed upon and'frozen to theroughened backing;

Figure? illustrates one method of pressing my modified backing plateinto contact with the copy relief so that the dope material disposedtherebetween will take the embossed impression;

Figure 8 shows my modified printing form as completely constructed;

Figure 9 is an enlarged microscopic detail of the printing form shown inFigure 3, taken along line 9-9 of the figure, this view illustrating theapproximate comparative thickness of the various parts making up theprinting plate; and

Figure 10 is an enlarged microscopic detail of my modified printing formtaken along line Ill- H] of Figure 8, this View 'llustratin'g theapproximate comparative thickn ess of the various parts making up thisprinting plate.

Similar reference characters refer, to similar parts-throughout theseveral views of the drawings.

In carrying out my invention I provide a backing plate preferablycomposed of metallic or other material which will withstand considerablepressure without stretching or distortion, which is preferably, andwhich has a low co-efiicient of expansion for ordinary roomtemperatures. I have found that copper is a very satisfactory metal touse for this purpose, although I do not limit myself to this materialalone, but I contemplate using other well-known materials which possessthe above characteristics, such as zinc, aluminum, ferrous and othermetals, fiber, paper, or composition materials, within the scope of thisinvention. The thickness of the backing sheet used will depend largelyupon the strength of the material and the ease with which it can be bentto conformto the surface of the printing cylinder. Where a copper plateis used a thickness of .015 to 0.1 of an inch has proven satisfactory,The backing sheet should be of uniform thickness throughout and somewhatlarger than the picture which it is to carry.

The top surface of the backing plate In may be granulated or roughened,as shown more particularly in Figure 1.- The purpose of roughening thebacking plate is to obtain a strong bond between the backing plate andthe cellulosic printing surface. Roughening of the backing surface, how-2,085,048 part of this app ication and illustrating certain ever, is anexpedient to obtain a strong bond, and where certain backing materialsare used, such roughening of the surface thereof may be unnecessary. Theroughened backing plate is positioned over the copy relief II, as shownin Figure 2. Any form of copy relief may be used. For purposes ofillustration, however, I have shown a copy relief having a gelatinesurface l2 thereon suitably hardened and swollen with water in thewell-known manner. The relief surface is produced in the well knownmanner which comprises photographing the object to be reproduced,exposing the sensitized gelatin surface through theiphotographic platecarrying the object image, screening the object image im-- pressed uponthe sensitized gelatin by either intaglio or half tone screens andfinally immersing the screened, image impressed gelatin surface in awater bath. A water swollen gelatin copy relief is thus producedcarrying toned impressions of delicate shading which may or may not bescreened depending upon the object to be produced. A dope material I3 isplaced over the copy relief and between the copy relief and the backingplate H]. The dope material may comprise nitrocellulose, celluloseacetate, collodion, or cellulose esters of other acids, dissolved in asuitable solvent. The solvents used may be one or more of the manywell-known solvents in commercial use, or a mixture of two or more of tem, such as ethyl acetate, butyl acetate, butyl alcohol acetone,alcohol, amyl acetate, and similar commercial solvents. Various lacquersin commercial use, shellac plastics dissolved in alcohol or likesolvent, cold plasticizable phenolic resins and similar materials havingcharacteristics of the cellulosic materials mentioned above,-may also beused. All of these materials, initially moldable and adapted to take anembossed impression and maintain the same upon solidification, are to beconsidered as encompassed by the terms dope material, cellulosicmaterial and cellulose solution as hereinafter used.

As shown in Figure 2, a heavy roller I 4 is moved over the backing plateto press the dope material into the photographically toned fine groovesof the copy surface [2. The dope material I3 is then allowed to hardenand set and soon becomes cemented or frozen to the roughened surface ofthe backing plate and takes an embossed photographically tonedimpression 'of the copy relief. When the dope material has becomethoroughly hardened, which generally requires from fifteen to fiftyminutes, the backing plate, with the cellulosic material l3 carrying theembossing frozen thereto, can be lifted or torn from the copy relief. Ithen have the complete printing form as shown in Figure 3 toned by theshaded photographic impressions carried by the hardened gelatine copyrelief. If the backing plate is made of such material as theplasticizable mass which takes the printing impressions, the mass willfirmly adhere and become bonded to the backing plate. For example, aviscous cellulosic mass will firmly adhere to a cellulose ester sheetand, if desired, a preformed cellulose ester sheet may be used as thebacking plate. After the molded plastic masshas become hardened andfrozen to the cellulose sheet, the copy relief may be separatedtherefrom and the cellulose backing sheet may be secured by means of asuitable adhesive to an additional backing sheet formed of metal orfibrous material.

' In making this type of printing form the dope material l3 must possessconsiderable body so that when fully set and hardened it will be ofsufficient thickness to take the full impression from the copy relief,and in addition to completely cover the backing plate l so that no spotson the backing plate are left uncovered. When a dope of medium viscosityis used in connection with ordinary paper printing, a microscopic crosssectional view appears to show that the embossed-impressions do notgenerally extend into the dope layer l3 more than to the thicknessthereof, as shown in Figure 9.

Ihave shown in Figure 4 a casting table which can be adjusted so as topresent a table surface which is absolutely level. This table is used incasting a modified form of printing plate, which will now be described.The backing plate Illa of suitable material, and similar to backingplate Ill heretofore described, is placed flatly upon the table surface.The table is preferably provided with a glass top 20, having an absolutesmooth and even top surface. The glass table top 20 may be supported bya tripod 2!, having three supporting legs 22. Three rectifying oradjustment screws 23 are provided by means of which the table surfacecan be leveled in the well-known manner. Spirit levels 24 are attachedto the sides of the table top 20. By observing the spirit levels 24 andmanipulating the adjustment screws 23,

the table surface can be placed in an absolutehorizontal plane. v

The backing plate Illa should possess no buckles or indentations andshould be smooth and even so as to lie absolutely fiat on the table top20 with the granulated or roughened surface thereof facing upward. Acellulosic material 25 dissolved in a suitable solvent and havingsubstantially the ingredients contained in dope material 13 abovedescribed is then poured from a suitable container 26 upon theapproximate center of the backing plate as it lies upon the leveledtable. The cellulosic material should flow easily and to obtain thisresult an excess of solvent may be added. The cellulosic material 25,

I sufliciently liquid, will flow evenly over the roughened surface ofthe backing plate and assume its own level. Sufficient material shouldbe poured on the backing plate to cause it to flow over all the edges ofthe plate. Suitable troughs 21 are provided to catch the overflow, thetroughs 21 being so constructed as to conduct the cellulosic material bygravity into a receiving pipe 28 from which it can be caught in asuitable receptacle.

After the backing plate Illa has been completely covered with thecellulosic material 25, the pouring is stopped and the cellulosicmaterial is allowed to set and harden in a clean, dry, and dustlessroom, freezing to the backing plate and forming a hard cellulose sheet.The cellulose sheet thus formed on the backing plate Illa may be from.005 to .015 of an inch thick, which is amply sufficient since thebacking plate takes the strain when the printing form is attached to therotating printing cylinder. If at any time it should prove to bedesirable to make the cellulose sheet of greater thickness, it would beonly necessary to place a frame wall around the backing plate as it lieson the casting table and thus contain the dope material upon the castingtable and prevent it from running off. The dope material would, ofcourse, assume its own level as before and the proper amount of liquidmaterial to pour upon the backing plate to produce the required sheetthickness could be accurately gauged, either by measuring the amount ofdope material poured upon the backing plate or by measuring the depth ofthe dope material spread over the backing plate.

I have shown in Figures 5 and 6 the product as removed from the castingtable shown in Figure 4. The cellulosic material 25 hardens into aglass-like sheet and becomes frozen to the roughened surface of thebacking plate Illa. Any unevenness or irregularity in the thickness ofthe backing plate Illa is compensated for by the cellulose sheet 25 whencast upon the backing plate by the method illustrated in Figure 4. Aprinting form of uniformthickness, when properly placed upon and securedto the printing cylinder, will present a printing surface which isabsolutely round.

I have illustrated in Figure 7 one method of molding the printing platefrom the copy relief II. The method of molding, shown in Figure '7,

is not essentially different fromthat shown and described in connectionwith Figure 2. The printing plate, with the cellulose sheet 25 facingdownward, is rolled or otherwise pressed into contact with thephotographically toned gelatine surface l2 of the copy relief I l. Dopematerial I3a. is rolled between the gelatine surface of the copy reliefII and the cellulose side of the printing plate as before. The materiall3a may comprise a plastic mass having a composition similar to thedope? material I3 above described. When the molding material I3a hasbecome sufficiently set and frozen to the backing plate, the whole islifted from the copy relief II. I then have my modified printing form ascompleted and shown in Figure 8. It is understood that my invention isequally applicable to the making of any and all forms of cast printingand reproduction plates and is not limited alone to intaglio and halftone printing forms, printing plates having the most delicate tones andcolor shadings can thus be produced.

The backing plate of my printing forms as made above takes the strainoff from the mechanically molded, photographically toned surface whenthe form is attached to the rapidly rotating printing cylinder, andpossesses sufficient strength to carry the printing pressure withoutstretching, shrinkage or distortion. The dope material carrying themolded surface does not assume any of the strains incident to printing.When my printing form as above constructed is properly-applied to theprinting cylinder no stretching whatever of the printing form occurs,and all areas of the printing form remain in exactly the same positionas first placed throughout the most tedious printing operation. Exactregistry between the colored parts of the printed work is thus assured.Furthermore. mv

printing form as above constructed is strong and durable, adapted forthe heaviest printing work, and can be quickly and easily made frominexpensive materials, with inexpensive equipment and with the use ofunskilled labor.

' As many changes could be made in the construction and method aboveoutlined and as many apparently widely different embodiments of thisinvention could be made without departing from the scope thereof, it isintended that all matter contained in the above description or shown inthe accompanying drawings shall be interpreted as illustrative and notin a limiting sense.

What I claim is:-

1. The method of preparing printing forms fromaphotographicallytonedwater swollen copy relief which comprises, placinga viscous plastic mass' material in solution of cellulosic material uponthe copy relief, applying a backing plate of, non-stretchable materialover the plastic mass, and rolling said plate against said copy reliefto spread said plastic mass therebetween.

2. The method of preparing printing forms from a copy relief whichincludes, placing a backing plate in a horizontal plane, coating saidbacking plate with a binding material, placing a plastic mass ofcellulosic material upon the copy relief, cold pressing said backingplate with the binding material attached thereto against said copyrelief, allowing the plastic material to harden and unite itself to saidbinding material, and removing the thus molded platefrom the copyrelief.

3. The method of preparing printing forms from a copy relief whichincludes, placing a backing plate of non-stretchable material in ahorizontal plane, coating said backing plate with a binding material,placing a plasticizable mass upon the copy relief, cold pressing saidbacking plate with the binding material attached thereto against saidcopy relief to spread the plastic mass therebetween, allowing theplastic mass to harden and unite itself to said binding material, and

removing the thus molded plate from the copy from a copy relief whichincludes, roughening' one side of a backing plate, placing said backingplate in a horizontal plane, flowing cellulosic material in solutionover said backing plate, and

allowing said cellulosic material to set, harden and freeze to theroughened side of the backing plate, placing a plastic mass upon thecopy relief, and cold pressing said backing plate with the cellulosicmaterial attached thereto against said copy relief to spread the plasticmass therebetween.

5. The method of preparing printing forms from a, copy relief whichincludes, roughening one side of a backing plate, placing a plastic massof cellulosic material upon the copy relief, and rolling the roughenedside of said plate against the copy relief to spread the plastic massbetween said plate and copy relief.

6. The method of preparing printing forms from a copy relief whichincludes, placing a back ing plate in a horizontal plane, flowingcellulosic over said backing plate, allowing said .cellulosic materialto set, harden and freeze to the backing plate, placing a plastic massupon the copy relief, and rolling said backing plate with thecellulosicmaterial attached thereto against said copy relief to spreadthe plastic mass therebetween.

7. The method of preparing printing forms from a copy relief whichincludes, placing a backing plate in a horizontal plane, flowingcellulosic material in solution over said backing plate, allowing saidcellulosic material to set, harden and freeze to the backing plate toform a layer, placing a plastic mass of cellulosic material upon thecopy relief, rolling said backing plate with the cellulosic materialattached thereto against said copy relief to spread the plastic masstherebetween, allowing the plastic mass to harden and unite itself tosaid cellulosic layer and removing thethus molded plate from the copyrelief.

8. The method of preparing forms from a photographically toned, copyrelief which commass, and cold pressing said plate against the copyrelief to spread said plastic mass therebetween, allowing the plasticmass to harden and uniteitself to said backing, and removing the thusmolded plate from the copy relief.

-9. The method of preparing printing forms which comprises forming'agelatine copy relief, juxtaposing a cellulose ester plate to the copyrelief, interposing a viscous plastic mass of a cellulose ester betweenthe plate and copy relief and rolling said plate into intimate contactwith said copy relief, whereby said mass receives a fine impression ofthe copy relief, and maintaining the plate and copy relief. in contactuntil said mass has been transformed to the solid phase. p

10. In the procem of preparing printing forms, the steps of imposing aviscous plastic mass comprised of a cellulose derivative and a volatilesolvent therefor upon a gelatine copy relief, by a rolling contacttherebetween, maintaining the mass and the relief in contact until saidvolatile solvent has volatilized and the mass hardened, and thereafterremoving the hardened plastic from the copy relief.

11. In the process of preparing printing forms from a gelatine copyrelief, the steps that comprise placing a viscous plastic masscomprising a cellulosic derivative and a volatile solvent therefor uponthe copy relief, applying a solid sheet of a cellulosic derivative overthe plastic mass, cold rolling said sheet against said copy relief tospread the plastic mass therebetween, maintaining the sheet and copyrelief in contact until the solvent of the plastic mass has volatilizedand the mass has hardened and united itself to said plate, andthen'removing the thus molded plate from the. gelatine relief.

12. In the process of preparing printing forms from a gelatine copyrelief, that has been developed, hardened and swollen with water, thesteps that comprise placing a highly viscous so- .lution of a cellulosederivative in a volatile sollief.

13. The method of making printing forms from a copy relief whichincludes applying to said copy relief, near one end thereof, arelatively viscous mass comprised of a cellulose ester and a volatilesolvent therefor, placing a backing sheet comprised of a cellulose esterthereover, and cold rolling the backing sheet against the plasticmaterial while extenuating the surface of the material laterally so asto force the material into the interstices of the copy relief, andmaintaining the backing sheet and copy relief in contact until thevolatile solvent has volatilized and the plastic nrilassJ hasautogenously bonded to the backing s ee I 14. A process of preparingprinting forms which includes the steps of imposing a viscous mass of acellulose ester and a volatile solvent upon a gelatine-copy relief byapplying a backing sheet of a cellulosic material to the mass andprogressively compressing the backing sheet against the copy relief by arolling pressure.

15. The method of preparing printing forms from a photographically tonedcopy relief which includes, placing a viscous moldable mass upon thecopy relief, applying a backing sheet formed from material which has anaflinity for said plastic mass over the plastic mass, and coldpressingsaid backing against the copy relief to spread said plastic masstherebetween, allowing the plastic mass toharden and unite itself tosaid backing, and removing the printing form from the copy relief.

16. The method of preparing printing forms which includes, forming awater-swollen gelatine copy relief, placing a backing in juxtapositionto the copy relief, interposing a viscous moldable mass between thebacking and copy relief, and rolling said backing and said copy relieftogether whereby said mass receives a fineimpression of the copy relief,and maintaining the backing and copy relief with the plastic massinterposed therebetween in position until said mass has been transformedto a solid phase, and thereafter removing the copy relief.

17. In the process of preparing printing forms from a water-swollengelatine copy relief, the steps that comprise placing a viscous moldablemass rendered plastic by the application of a solvent upon the copyrelief, applying a solid backing sheet having an afiinity for saidplastic mass over the plastic mass, cold-rolling said sheet against saidcopy relief to spread the plastic mass therebetween, maintaining thesheet and copy relief in contact until the solvent in the plastic massis volatilized and the mass has hardened and united itself to saidplate, and then removing the thus-embossed plate from the gelatinerelief.

18. In the process of preparing printing forms from agelatine copyrelief that has been developed, hardened and swollen with water, thesteps that comprise providing a viscous moldable mass renderedmoldableby a volatile solvent, placing said mass between the gelatinecopy relief and a substantially non-stretchable backing, rolling saidbacking and gelatine copy relief to spread said plastic masstherebetween, maintaining the backing and copy relief in contact untilthe solvent is volatilized and the plastic mass has become hardened andbonded to the backing,

and then removing the copy relief from the printing form.

OSWA LD R. SCHULTZ.

